Deputy Secretary of State John Sullivan will represent the United States at the regional meeting scheduled for Monday to Wednesday in the resort city of Cancun.

World Bulletin / News Desk

US Secretary of State Rex Tillerson on Friday cancelled his attendance at next week's Organization of American States meeting in Mexico, opting to stay in Washington to focus on the diplomatic crisis in the Middle East.

"The secretary of state will continue his efforts to de-escalate tensions in the Middle East region through in-person meetings and phone conversations with Gulf and regional leaders," the State Department said in a statement.

But last week, US President Donald Trump expressed support for the Saudi-led allegations, charging that Qatar had "historically been a funder of terrorism at a very high level."

Pentagon and State Department officials have since scrambled to reassure the emirate, which hosts the largest US airbase in the Middle East and the command headquarters for operations in Iraq, Syria and Afghanistan.

On Thursday, the United States agreed to a $12 billion warplane sale to Qatar, reaffirming its support.

Tillerson "has made more than a dozen phone calls and participated in several in-person meetings" in efforts to tamp down the crisis, the State Department said.